Not sure if this is the right section to post this question but.... I'm installing cellular shades on all my windows. Most have gone up without too much trouble, but with two of my windows when I try and screw the bracket to the inside upper window frame, the screw remains lose and just spins around. I have tried longer screws and self-tap screws but nothing holds. The installation is basically just a bracket that uses two screws to secure itself to the inside upper ledge/frame of the window. Are there any special tools needed to complete this? Thanks!